Pack or skip
Flip-flops for San Francisco in September
Verdict
Optional
Warm enough to wear in the evening or on the beach; not on a city walking day.
Why
San Francisco in September averages highs of 70°F, lows of 57°F, 2 rainy days.
That climate makes flip-flops a judgment call. Warm enough to wear in the evening or on the beach; not on a city walking day.